In the construction of metal buildings, for example, buidlings having corrugated sheet metal walls and roofs, insulating materials with moisture impervious facings line the inside for purposes of insulating the building as well as improving appearance. The roofs of such buildings presented problems when blanket of glass wool insulation is used. Unless the blanket was supported on close centers, it had a tendency to sag giving an unsightly appearance. If the facing was to form a moisture impervious surface, tabs extending from the longitudinal margins of the blanket insulation were required to be stapled or glued together. Often a sealing strip was secured over the longitudinal seam between blankets.
One approach for an insulating layer in the above type construction is the use of a rigid or semi-rigid board of felted fibers. Such board has heretofore been cut in relatively short lengths to facilitate handling and shipping. These short lengths require frequent end joints which increase the potential for heat loss and are unattractive. When faced with a sheet of a material providing vapor barrier, and in some instances a decorative finish, the end joints of the facing require additional installation effort and further detract from the final appearance.
The present insulating material overcomes the above problems with a rigid or semi-rigid roll of blanket insulation having a length suitable to span a plurality of framing elements and frequently of such length as to extend across an entire building surface. For example in roof installations, the board may extend the length of the roof and offer sufficient rigidity to resist sagging between purlins on 4 - 6 foot centers. In addition, the insulating material has a tab of facing material extending from its margin with sufficient stiffness for overlapping an adjacent blanket. This tab is protected in shipping to maintain its shape allowing the blankets to be butted and a relatively impervious seal obtained between blankets without stapling or gluing.